Adjustable strut



1. E. HODGES. ADJUSTABLE STR UT. APPLICATION FILED DEC.8, 1916.

Patented J11ly 26, 1921.

UNITED s T s sl PA'rEN OFFICE.

HJ'ESSE E. inonens, or COVINGTON, KENTUCKY.

' ADJUSTABLE STRUT.

Specification of Letters Patent. Patented July 26; 1921 Applicationfiled December s, 1916. Serial No. 135,776.

To all whom it, may concern:

-Be it known that I Jnssn E. Honcns, a citizen of the United tates, anda resident of Covington, in the county of Kenton and State of Kentucky,have invented certaln new and useful Improvements in Adjustable Struts,of which the following is a full, clear, and exact description,reference being had to the accompanying drawing, forming part of thisspecification.

This invention has relation to adjustable struts for supporting concreteforms in the construction of buildings. In devices of this nature thegreat weight which must be supported and the danger attendant upon thefalling or slipping of the work as Well as the.

damage caused bya fall demands very special construction of strut topermit of its being adjustable.

While it may be contested that a mere clamping strut is perfectly safefor supporting temporary concrete work, still many public buildingdepartments will not allow their use as they contend that imperfectassembly of them Will result in a slipping of the devices, and hencelarge damages and danger to concrete workers and others at work onbuildings. As a usual practice in the use of clamping adjustable struts,a compensating device such as a wedge or the like has often to be usedto takeup the slippage of the strut.

The object of this invention is to produce an adjustable strut which isdrawn together with a clamping device and when drawn together has alocln which will cause the supported weight to force the clamp intotighter position to prevent slipping.

This object and other advantages to be noted I accomplish by thatcertain construction and arrangement of parts to be hereinafter morespecifically pointed out and claimed.

In the drawing,

Figure 1 is a side elevation of my novel clamp lock strut in use.

Fig. 2 is a detail section through the locking member, showing a portionof the strut in side elevation.

Fig. 3 is a perspective view of a locking member of slightly differentshape.

Fig. 4 is a perspective view of the lock member shown in Figs. 1 and 2.

The adjustable strut shown consists in a central supporting column orstandard 1, on each side of which are side supports 2, 2

Thettandard l rests on the floor of the building or other strutsupporting surface and the side standards connected at the top means ofa block 3 support, the concrete workersforms as at f, or other weight tobe supported.

I In usual practice, I have found it Well to clamp the side members tothe central stands ard above the ends ofthe side members by means of aU-shaped strap 5 which, pivots at its open end a cam 6. By driving thiscam downwardly after slipping the strap up over the members 1 and 2, 2they will be clamped firmly together, but not sufficiently to preventslipping under unusual conditions. This upper clamp is not a requisite,but' I have found it valuable to prevent spreading of the side supports,as Well as to give further security.

The side support 2 is cut shorter than the side support 2, to permit ofa clamping of the one support against the central column and thelocating of the locking clamp beneath the end of the other. Two stoutmetal plates or straps 7 are provided,.connected at one end by the bolt8 and at the other by the bolt 9 so as to completely surround'thecolumn. On the bolt 9 is secured the clamp 10, which has a suitable camface such that when it is driven down by a hammer the face will comeinto constantly closer contact with any member inside of the straps orlates.

On the bolt 8 is mounted a clamp lock 11, which has a curved roughenedface 12, which is adjacent the bolt'holes 13 in the clamp lock. The boltholes are set so that the face 12 is eccentric to them, or else thecurved face can be made in the shape of a cam also. The clamp lockextends upwardly from the bolt holes for a considerable distance and isthus set so that pressure on the upper end thereof as at 14 will tend toforce the roughened surface to swing inwardly against any member betweenthe straps.

For convenience, the clamp lock is provided with a slot or slots 15through which passes a bolt 16. An angle plate 17. is pro vided which isadapted to be merely set, or if desired screwed onto the end of thestrut 2* and in the corner of this angle plate is I located the head ofthe bolt so that the lock is held against falling away from the corneror angle plate. The clamp locks thus have the curved surface meeting theflat surface 18 which extends up to the angle plate and the holes 13 forthe pivot bolts are at the apex of the flat and the curved surfaces.

In using the device, which is set over the central column when the strutis being put up, the plates or straps are moved up until they lie in aposition along the end of the side support 2 and just beneath the end ofthe side support 2*. The angle plate is then a position with itsroughened face against the central standard, and with its upper edgeforced up against the angle plate. In

this position, any weight or force applied downwardly on the standard 2will tend to force the look more firmly into place and also to draw thecam clamp more firmly into place. There is therefore the possibility ofadjustments by regulating the relation of the side supports and thecentral support or column and the positive locking of the parts in placeby the driving down of the cam clamp. I

In the showing in Figs. 3 and 4, the difference is that the clam lock inone instance has a central web 20 ig. 3) and two slots for the securingboltsto the angle plate for the short side standard. In another instancethere is no central web and there is but one slot 15' (Fig. l). The twoclamp locks are otherwise the same except for the greater width of theshowing in Fig. 3 for the curved and roughened surface, the said showingbeing such that the part can be made of lighter metal than the one shownin Fig. 4, thereby gaining a small saving in cost of production. I

7 It is practical to dispense with the cam clamp in this device and usetwo clamp locks instead. No-such showing is illustrated,

fixed as soon as but it will be understood that with two clamp locks thedevice would have to be driven up into place as shown in Fig. 1whereupon the clamp locks would remain downward pressure was applied onthe side supports.

This is not the preferred form of my invention, because it is much lessconvenient to use, and has more chance of being improperly installedwith the resultant dangers from slipping or dislodgment of the parts.

The preferred embodiment as illustrated and above described is easy toinstall and fool-proof to a very high degree, as the only waythe devicecan be set in place at all is theproper place, and'the mere driving downof the cam clamp bringsthe parts into lockin position. 7

Ilaving thusdescribed my invention, what I claim as new and ters Patent,is

In an adjustable strut, the combination with a central desire to secureby 'Letstandard and side supports lying alongthe sides thereof, one ofthe side supports-being shorter than the other,

a frame surroundingthe standard, a cam clamp pivotally mounted at oneend of the frame, and a clamp lock pivotally mounted at the other end ofthe frame, with said frame located horizontally on the standards, withthe camclamp in a position to engage the longer side support and forceit against the central standard, and the clamp lock to engage theunderside of the short side sup port and the side of the centralstandard with a U-shaped clamp provided with a cam to engageand pressthe side supports together, "located above the lower ends of the sidesupports, to hold the side supports temporarily prior to adjustmentofthe lower support, for the purpose described. I

